Hang on S/W Upgrade screen on P970Support

I've tried to update my P970 to Gingerbread using the LGMobile Update Tool.

During the update my phone hangs to the S/W Upgrade screen and the Update tool says that "Problem with communication between cell phone and PC".

It instructs you to disconnect the USB, remove the battery and install the battery, Power on the phone connect the USB and press the restart button on the Update tool. But it goes back to the "Problem with communication between cell phone and PC".

I cannot use my phone as it is stuck on the S/W Upgrade screen! even if i took off the battery and put it back.

I also tried to press the volume up + Power button, volume down + Power button, G + Power button, but to no avail....